Weedkiller Fuels Superbug Spread?

A new study indicates that antimicrobial resistance (AMR), a major global health threat, might be exacerbated by the widespread use of weedkillers, particularly glyphosate. Researchers were surprised to find that multidrug-resistant bacteria, often found in hospitals, not only resist multiple antibiotic classes but also high concentrations of glyphosate.

These resistant bacteria were found in sediment samples from a protected nature reserve north of Buenos Aires, Argentina, where herbicides are not used. Despite this, the bacteria demonstrated resistance to glyphosate and glyphosate-based herbicides, suggesting that resistant bacteria can spread beyond areas where these chemicals are applied.

The study further compared these findings to hospital-sourced strains, revealing that 74 percent were resistant to carbapenems, a crucial class of antibiotics. Notably, all hospital strains also showed resistance to glyphosate and its related herbicides.

This raises concerns that if hospital wastewater containing these resistant bacteria enters the environment, they could proliferate in agricultural areas where glyphosate is frequently used. Waterways may serve as a conduit for the movement of these resistant bacteria between hospitals and agricultural settings.

In Canada, glyphosate is the most extensively used herbicide, regulated by Health Canada. While its use is subject to scientific assessment and periodic re-evaluations, some regions like Ontario and Quebec prohibit its use for residential lawn and garden care. Globally, other countries have implemented stricter bans on household applications or use in public spaces.

The study's authors are calling for policymakers to include AMR testing when evaluating glyphosate products. They propose that policies mandate co-selection testing with antibiotics before pesticide marketing and suggest warning labels about the potential spread of antibiotic resistance genes from contaminated soils to hospitals via untreated water.